Preparation of certain foods and beverages can involve blending, whipping, stirring, etc., the food or beverage. This may be done using a rotary blade or mixer which is lowered into a container holding the food or beverage, or which is held in place as the container is advanced towards the rotary blade/mixer to move the container's contents into contact with the blade/mixer.
In Applicant's U.S. Pat. Nos. 6,474,862, 6,326,047 and 5,803,377, entitled APPARATUS AND METHOD FOR MAKING FROZEN DRINKS, the disclosures of which are incorporated herein by reference, methods for making frozen drinks are described. These patents describe a machine that allows a milkshake or other frozen drink to be quickly made from a block of ingredients pre-frozen into a serving cup. The frozen contents within the serving cup are broken into small frozen particles using a rotating blade, and blended with an added liquid also using the rotating blade.
According to the patents, when a milkshake or other frozen drink is to be made, a serving cup containing the frozen block is positioned in a cup holder which forms a part of the frozen drink machine. A rotating blade is lowered into the cup and bores through the frozen substance in the cup, grinding it into small frozen particles. As the blade moves towards the bottom interior of the cup, milk, water, or another liquid is added to the cup and is blended into the frozen substance by the rotating blade. Alternatively, the rotating blade may be held at a fixed elevation, and the cup may be advanced towards the blade to move the cup's contents into contact with the blade. In either case, the cup and/or blade may be reciprocated to allow the full contents of the cup to be mixed.
During mixing, material can splash from the cup onto the drink machine and surrounding area. U.S. Pat. Nos. 5,328,263 and 5,439,289 (Neilson) each describe a separate, dedicated lid placement mechanism that positions a lid onto a cup so as to minimize such splashing when the contents of the cup are being mixed. U.S. Pat. No. 5,145,250 (Planck) describes a mixing device wherein a lid and mixing device move axially together until the lid makes contact with the receptacle, at which time springs keep the lid in contact with the receptacle as the mixing head travels further into the receptacle. In each case, there is potential for carryover of mixed ingredients from one batch to the next. In Planck, a disposable cover over the pressure plate of the lid is described. In Neilson U.S. Pat. No. 5,439,289 a provision for a releasable lid connector means is claimed to enable cleaning of the lid remotely from the mixing device. It is further desirable, however, to provide a drink mixer having a splash shield that may be automatically rinsed following mixing of each batch or beverage, preferably without disassembly or removal of any components or disposable covers.